<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
	</body>
</html>
<body>
	<input type="number" id="shu">
	<button id="btn">查询输入数据的范围</button>
</body>
</html>

<script>
	
	btn.onclick = function(){
		var Tval = parseInt(shu.value);
		if (Tval>0) {
			alert("大于0");
		}else if (Tval==0){
			alert("等于0");
		}else if (Tval<0){
			alert("小于0");
		}else{
			alert("请输入数字.....")
		}	
	}

</script>